As construction for the Delaware Avenue transportation enhancement project continues this summer, a unique feature of the new street-side landscape will promote green infrastructure solutions to Wilmington’s water challenges.

Building on TheDCH’s portfolio of recent stormwater management projects, three bio-retention areas will use water-filtering plants, trees, and a special soil composition to collect, absorb, and filter storm water. In addition to serving as beautiful plantings along Delaware Avenue, these features will serve to reduce the volume and speed of stormwater runoff in a particularly important area for addressing Wilmington’s combined sewer overflow (CSO) challenges. Green infrastructure solutions increase our resilience to heavy rain events and storms using natural features and the inherent power of plants.

This 2015 project adds to two other projects completed by TheDCH in 2014 – the Locust Street and Thatcher Street tree trench projects. Similarly, these features in northeast Wilmington serve to collect, filter and absorb stormwater runoff in this strategic CSO area using both above-ground and below-ground technologies...or as we at TheDCH refer to them, trees and soil!

In addition to increasing traditional areas for ornamental plantings – without impacting pedestrian passage and available parking – these projects create more room for tree growth, connected soil space for root zones, and more surface area for water absorption. So in the long run, this will reduce the familiar conflicts between street trees and sidewalks, promote healthier trees, and prolong the life spans of street trees – all important factors for expanding and protecting our urban tree canopy for the future.

TheDCH thanks our project partners for support and technical assistance in completing these projects: USDA Forest Service, DE Dept. of Natural Resources & Environmental Control (DNREC), DE Dept. of Transportation (DelDOT), New Castle Conservation District, City of Wilmington, and Whitman, Requardt & Associates, LLP (WRA).

Thatcher St. – oak closeup

Swamp white oak trees (Quercus bicolor), suitable for growth and adaptation to frequent standing water, now line the corner of Thatcher St. and E. 23rd.

Thatcher St. – row of trees photo

The Thatcher Street tree trench collects stormwater runoff from the street below grade level, where it can be slowed, absorbed, and filtered as it permeates the soil as groundwater.

Thatcher St. sign

The Thatcher Street tree trench features interconnected drainage areas that also serve to expand areas for root growth.

Delaware Ave. photo

Currently under construction this summer, this below-ground bio-retention area at DE Ave./Lincoln St. will soon feature water-absorbing ornamental plants and trees.

I value the Delaware Center for Horticulture for its work to transform Wilmington by making it a greener, more beautiful and more livable place for all. By planning,...►